'91 V6 3.0 4Runner. While I was replacing the valve cover gaskets, I had to pull the EGR system... when I pulled the tube out of the intake chamber, I noticed a black gooey substance on the end of the tube and in the chamber where the tube inserts. I spoke to a Toyota Machanic at the dealership and he said they all build up this deposit but he couldn't tell me what it is or what causes it! Anybody know what it is? Anyway to remove it chemically? Any body else see it in their Toyo?

Thanks

 

Yup, saw the same stuff when doing the Airaid MIT (ISR) mod. I have no clue what is either. Al I know is that I cleaned it off with some mild degreaser and a rag. (I have the 3.4L)

 

carbon.. some carb and choke clear will do the trick